runtime(doc): usr_05: packadd in a vimrc needs the "!"

Problem:  Four of the package sections tell the reader to load the
          plugin with "packadd", and the comment one goes on to talk
          about putting that line in the vimrc file.  Without the "!"
          the package is loaded there and then rather than during the
          usual startup, which is not what a vimrc wants.  The matchit
          section then explains the help file being found by saying
          ":packadd" loaded the plugin, which is what the "!" keeps it
          from doing.
Solution: Give every package section the same line to write, correct the
          reason the help file is found, and say once, where the
          packages are introduced, which of the two forms belongs in a
          vimrc.

closes: #21186

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/usr_05.txt

@@ -1,4 +1,4 @@
-*usr_05.txt*	For Vim version 9.2.  Last change: 2026 May 11
+*usr_05.txt*	For Vim version 9.2.  Last change: 2026 Aug 30
 
 
 		     VIM USER MANUAL	by Bram Moolenaar
@@ -406,6 +406,10 @@ packages: optional and automatically loaded on startup.
 
 The Vim distribution comes with a few packages that you can optionally use.
 
+In your |vimrc| use `:packadd!`: it only adds the package to 'runtimepath'
+and leaves the loading to the usual startup.  Without the "!" the package is
+loaded directly, which is what you want when trying one out.  See |:packadd|.
+
 ------------------------------------------------------------------------------
 Adding the matchit package		*matchit-install* *package-matchit*
 ------------------------------------------------------------------------------
@@ -413,14 +417,14 @@ For example, the matchit package  This plugin makes the "%" command jump to
 matching HTML tags, if/else/endif in Vim scripts, etc.  Very useful, although
 it's not backwards compatible (that's why it is not enabled by default).
 
-To start using the matchit plugin, add one line to your vimrc file: >
+To start using this plugin, add one line to your vimrc file: >
 	packadd! matchit
 
 That's all!  After restarting Vim you can find help about this plugin: >
 	:help matchit
 
-This works, because when `:packadd` loaded the plugin it also added the
-package directory in 'runtimepath', so that the help file can be found.
+This works, because `:packadd!` added the package directory in 'runtimepath',
+so that the help file can be found.
 
 You can find packages on the Internet in various places.  It usually comes as
 an archive or as a repository.  For an archive you can follow these steps:
@@ -442,11 +446,10 @@ an archive or as a repository.  For an archive you can follow these steps:
 Adding the editorconfig package *editorconfig-install* *package-editorconfig*
 ------------------------------------------------------------------------------
 
-Similar to the matchit package, to load the distributed editorconfig plugin
-when Vim starts, add the following line to your vimrc file: >
+To start using this plugin, add one line to your vimrc file: >
 	packadd! editorconfig
 
-After restarting your Vim, the plugin is active and you can read about it at: >
+After restarting Vim the plugin is active and you can read about it at: >
 	:h editorconfig.txt
 
 
@@ -454,14 +457,13 @@ After restarting your Vim, the plugin is active and you can read about it at: >
 Adding the comment package		*comment-install* *package-comment*
 ------------------------------------------------------------------------------
 
-Load the plugin with this command: >
-	packadd comment
+To start using this plugin, add one line to your vimrc file: >
+	packadd! comment
 <
 This way you can use the plugin with the default key bindings `gc` and similar
 for commenting (which is a well-established mapping in the Vim community).
 
-If you add this line to your vimrc file, then you need to restart Vim to have
-the package loaded.  Once the package is loaded, read about it at: >
+After restarting Vim the plugin is active and you can read about it at: >
 	:h comment.txt
 
 
@@ -469,8 +471,8 @@ the package loaded.  Once the package is loaded, read about it at: >
 Adding the nohlsearch package	*nohlsearch-install* *package-nohlsearch*
 ------------------------------------------------------------------------------
 
-Load the plugin with this command: >
-	packadd nohlsearch
+To start using this plugin, add one line to your vimrc file: >
+	packadd! nohlsearch
 <
 Automatically execute |:nohlsearch| after 'updatetime' or getting into
 |Insert| mode.
@@ -485,8 +487,8 @@ To disable the effect of the plugin after it has been loaded: >
 Adding the highlight-yank package	*hlyank-install* *package-hlyank*
 ------------------------------------------------------------------------------
 
-Load the plugin with this command: >
-	packadd hlyank
+To start using this plugin, add one line to your vimrc file: >
+	packadd! hlyank
 <
 This package briefly highlights the affected region of the last |yank|
 command.  See |52.6| for a simplified implementation using the
@@ -523,8 +525,8 @@ The following configuration variables can be used are "g:hlput_hlgroup" and
 Adding the osc52 package		*osc52-install* *package-osc52*
 ------------------------------------------------------------------------------
 
-Load the plugin with this command: >
-	packadd osc52
+To start using this plugin, add one line to your vimrc file: >
+	packadd! osc52
 <
 The osc52.vim package provides support for the OSC 52 terminal command, which
 allows an application to access the clipboard by communicating directly with